Process for preparing high molecular weight hydrocarbons



Patented Mar. 17, 1953 PROCESS FOR PREPARING HIGH .MOLECU; LAB WEIGHT HYD R'OCARBONS'" William F. Gresham, -Wilming-ton, DeL, assignor to -E. I. du Punt-dc Nemours' and Company; Wilmington, Del., a corporation oft-Delaware.

No-Drawing.v Application November 3,1951; Serial No. 254,804

3i Claims. (Cl. 260-449) This invention relates to a catalytic process for preparing high molecular weight hydrocarbons. More particularly, it relates to a process for synthesizing high molecular weight polymethylenes- 2,352,345 and 2,352,323; Br. Patent 468,434) High" molecular weight straight chain alcohols and other oxygen-containing organic compounds also have been obtained by hydrogenation of carbon monoxide in the presence of metalsof the eighth group suspended in paraffin'hydrocarbons (Patent Applications in the Field 'ofFischer-Tropsch' and Allied Reactionsivol. II, 1948, translated by Charles A. Meyer& 00., containing'the following German patent applications of 'I. G. Farbem'ndustrie Aktiengesellschaft: R106 854' IV D/120, January, 1940; 0. Z. 14 718 J/z, April 25, 1944; 0. Z; 14225 January 8, 1943; 0. Z. 14226 quite'recentlyit'has notbeen possible'to obtairr straight chain alcohols having from 3 to 50 carbon atoms per molecule efiiciently or in good yield (cf, the copending application of Hager and- I-Iowk, S. N. 87,114, filed April 12, 1949, which discloses the preparation of straight chain pri-" mary. alcohols from C and H2 using rutheniumv catalyst and water or alcohol as a solvent). Another very recent development in this art is the discoverythat the course of the (JO-H2" reaction in the presence of water and a ruthenium catalyst is determined by the pH of the medium; strongly alkaline media cause the formation of C2 to C alcohols (Gresham, S. N. 99,343, filed. June 15, 1949) rather than hydrocarbon waxes which are formed when'the pHis on the acid side. The waxes previously obtained in aqueous systems were produced simultaneously with compoundsof relatively low 1 molecular weight (Fischer and; Pichler, Brennstofi-Chemie 20, 247-50 (1939)); the average molecular weight of the reaction June 8, 1943; O. Z.l2 880 July 5, 1941). Until.

products being generally less'than:1000. In gerra eral these previously known waxy reaction prodw ucts contained ingredients which could be'disatilledat high temperatures: and lovwpressures: (200 C./2 mm);

An object of this invention is toprepare paraf fin waxes of improved quality and higherimolecu-l lar weight from carbon monoxide and hydrogen; Another object is to prepare relatively highamelting polymethylenes without isimultaneouslyyproducing oily products. Other" objects offthe-fimvention appear hereinafter:

It has been discovered in accordance-with --this invention that the molecular weight of I poly methylenes obtainable from carbon monoxide and.v hydrogenin the presence of water and a ruthe-- nium catalyst depends-not'only upon the acidity of the medium but also upon-the mol ratio of COrHz which is-employed. This-invention'provides a process for preparing polymethylenes of improved quality by introducing 'hydrogen, -car-- bon monoxide and water 'intoa reactionvessel themol ratio-0P CO1H2' being initially greaterthan 1 :1 and preferably from-2 1- to-'-12.5 :1', and heating the reactants in the presence 'of' aruthenium-containing catalyst and an acidic reagent (generally while controlling and maintaining the pH below- '2) at a pressure within==the=range=' on 100 to 3000 atmospheres, preferably 200 to 1000 atmospheres; at a temperaturewithin therange of 150 to 300 C.

In determining the nature of the reaction product obtainedin the reaction between CO and H2 in the presence of a ruthenium-containing catalystandwater, pH is..a very, important factor;

for example, if noacid .or alkali is added and" if the pH is not controlled, the reaction mixture becomes acidic due to the formation of carb'onf dioxide andat least traces of carboxylic acids,

and this acidity has a veryprofound' efiect uponi the subsequentcoursezof: thereaction, causing the formation of relatively longer chainprod ucts, such as waxy alcohols containing up to 50 or more carbon atoms per molecule. If the pH isiinitially strongly acidic, high-molecular weight waxy products :are produced in still greater pro-o portion,. and: waxy: paraffins .of relatively higher molecular..:weight are formed. This .is especially true ifiunder. these conditionstthe CO:I-I2,=ratio is high: This: isira. rather remarkable-s-discovery, because: paraflinsv are a richer: in hydrogeni than-t are low molecular weight alcohols, and the formation of alcohols should therefore normally be favored by increasin the CO:H2 ratio.

Ruthenium, and compounds thereof, are specific in their effect upon this reaction. Ruthenium is most conveniently introduced into the reaction mixture in the form of its dioxide, which is believed to be reduced in situ. It is quite possible that under the reaction conditions the ruthenium is converted to a ruthenium hydrocarbonyl, but the invention is not necessarily limited by any such explanation or theory.

The ruthenium-containing substances which may be employed in the practice of the invention include not only ruthenium metal, ruthenium oxides (e. g., dioxide, sesquioxide or tetraoxide), and ruthenium carbonyls (e. g., diruthenium nonacarbonyl, ruthenium carbonyl hydride), but also other ruthenium-containing compounds. such as ruthenium salts of organic carboxylic acids, which may give rise to the formation of a ruthenium carbonyl or hydrocarbonyl (or salt thereof) under the reaction conditions. The ruthenium catalysts may be used as such or on a support such as charcoal, alumina, silica gel, silicon carbon, pumice, etc. The quantity of catalyst which is employed is not highly critical, but it is desirable to use a sufiicient amount to efiect a reasonably rapid reaction, e. g., about 0.001% to about 20% by weight of ruthenium dioxide, or an equivalent weight of ruthenium in any other form, based on the total quantity of reaction mixture. The acidic agents which may be employed include hydrochloric acid, phosphoric acid, cresol, phenol, sulfuric acid, oxalic acid, hydroxyacetic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, hydrated BFs, benzene sulfonic acid, etc. In fact, any method for maintaining and controlling the pH, preferably at a level below about 2, may be employed.

The solid polymethylenes obtained under the preferred conditions disclosed herein have inherent viscosities of about 0.33 to 0.36, measured at 0.25% concentration in tetrahydronaphthalene at 125 C. The melting points of these polymethylenes are within the range of about 126 to 129 C., or slightly higher, it being understood that the melting point does not increase rapidly with molecular weight when the molecular weight is high, e. g. above about 2000.

It is preferable to mix the synthesis gas prior to the reaction, for example, by pressuring the from equal volumes of 20% aqueous sodium hydroxide and saturated aqueous hydroquinone solution. The gases may also be desulfurized by passing through a tower containing absorbent charcoal, or by conventional chemical desulfurization processes.

The reaction proceeds best within the relatively narrow temperature range of 180 to 225 C. Below C. the reaction is too slow or does not occur.

The pressure has a considerable influence on the course of the reaction. It has been found that at pressures of about 100 to atmospheres, when the reaction medium is acidic, the reaction product consists of hydrocarbon oils and low molecular weight waxes. On the other hand, at pressures substantially exceeding 1000 atmospheres, in either alkaline or acidic media, the reaction yields substantial quantities of volatile hydrocarbons, which is generally undesirable. Thus, the desirable pressure range for formation of highest molecular weight polymethylenes is between 200 and 1000 atmospheres, a still more preferred range being 300 to 1000 atmospheres.

It is often desirable to use in the reaction mixture a dispersing agent to facilitate the intimate mixing of all components, including the water. Any commercial dispersing agent that has no poisoning effect on the catalyst can be used for this purpose. For the same reason, agitation of the reaction mixture is desirable, although not essential.

The process may be carried out batchwise in a suitable pressure vessel. The progress of the reaction may be followed by the drop in pressure, the reaction being continued by further additions of carbon monoxide and hydrogen until an optimum amount of reaction product relative to the size of the vessel has been formed. The process may also be carried out continuously, for example by pumping the gas mixture and the liquid reaction medium at the required pressure over a fixed catalyst bed in a heated zone at a predetermined rate.

The effect of pH on the reaction between carbon monoxide and hydrogen in aqueous media at to 200 C. under 200 to 800 atmospheres pressure at reaction times of 2 to 6 hours in the presence of a ruthenium-containing catalyst (6 grams RuOz per 325 cc. of reaction space) is set forth in the following table (CO:H2=1:2)

N on- Gaseous Products cc 1111 tCC 1111 2- 10 a co 0 on 10- 15 a co 0 cut Wax Percent of gg (Percent of Total) (Percent of Total) iotal) H 1 0 0.33 molal (1.0 molal H) 1. 1 1. 8 24 3 grams 127). i fi' 21 A Pb h t B r 0.5 molal Nani P04 4 e 3 5 am (2517) 0 grams 988%) c1 10 05p a e 11 e 0,05 molal N HPO 6-6 1; 19 7' gt grams (75%)- None Nnnp .4 grams 36%).-. 5 grams (267).. 7.4 rams 38 0 5 molal 11. 5 7. 5 1e. 1 6.6 grams (39 3.7 grams (25% 6.4 grams 23853;. Na'HCOa 8. 3 7. 1 22 17 grams (77% 2 grams (10%). 8 grams (13%). NaOOHO do 7- 3 1 5 15 r ms 1%). 3.5 grams (19%). 1 Q mnla'l 11 19.6 17 grams (82%) 2.6 grams (13%). KHOO, 0 5 1 1 8. 0 8. 0 24 22 grams (91%).-.. 2.2 grams (9%).

reactants in a vessel fitted with a mixing or agitating means, although the gases may be introduced in the reaction apparatus separately and simultaneously, through bafiles or similar devices. If necessary, the gases may be previously deoxygenated, for example by reaction with hot copper or by treatment with a scrubbing solution prepared Polymethylene syntheszs an aqueous medza. contummy amd and RuOz con I't'l Pres 3 'o i D t H 1 1 Solute Comm or re Sure ion escnp 1on0 ro ratio pH Temp., oi Product (atm') 0. not

1:2- HBPOL- 3M 1 88-122 172-190 OiLandsoliddistillation residue. Distilled in part at 200 J2 mm.

1:2.--" HaPO4-- 85% (85% HaPO4+15% H) 1 320-515 175-206 122 Distillation of 23.1 grams gave 3.5 grams oil, B. P. 200l3 mm.

1:1 HaPO4- 85% 1 240-310 179-202 122 2:1. 1131 04.. 85% 1 250-320 180-188 128 Good film-forming resin. Entirely polymethylene.

4:1--." HzPO4 1 280-307 180-200 127 Do.

8:1 H;PO4 1 287-314 180-195 128.5 Do.

12.521" H3PO4 1 290-320 180-190 129 Good film-forming resin. Entirely polymethylene. Intrinsic viscosity =.329.

l Determined in tetralin at 125 0., conc.=0.25 gram/100 1111.

As can be seen by the foregoing description, this invention makes it possible to synthesize from carbon monoxide and hydrogen polymethylene hydrocarbons as the sole products, said polymethylenes having relatively high melting points, i. e. containing relatively small quantities of the distillable ingredients which lower the melting point.

The polymethylenes provided by this invention may be used as ingredients of chewing gum, impregnated paper, etc., and in the manufacture of chlorosulfonated polymethylenes, chlorinated polymethylenes, foils, fibers, molded products, adhesives including those made by peroxide curing, bags and other receptacles including those which are used as capsules for rubber-mix materials where the capsule is itself added to the rubber-mix, dispersions for coating materials, blends with polythene, polyisobutylene, etc.

This application is a continuation-in-part of my copending application S. N. 148,507, filed March 8, 1950, Which in turn is a continuationin-part of my application S. N. 99,343 which was filed on June 15, 1949, now U. S. Patent No. 2,535,060.

I claim:

1. A process for preparing polymethylenes which comprises introducing into a reaction vessel a mixture of carbon monoxide, hydrogen, water and an acidic reagent capable of maintaining the pH of the mixture below 1, the m'ol ratio of carbon monoxide to hydrogen being of from 2:1 to 12.521, heating the said mixture in the presence of a ruthenium-containing substance at a temperature within the range of 180 to 225 C. under a pressure within the range of 200 to 800 atmospheres, whereby a reaction occurs resulting in the formation of solid polymethylenes, and thereafter separating the said polymethylenes from the resulting mixture.

2. A process for preparing polymethylenes which comprises introducing into a reaction vessel ruthenium dioxide. carbon monoxide, hydrogen, water, and phosphoric acid, heating the resulting mixture at a temperature within the range of 180 C. to 225 C. and at a pressure within the range of 200 to 800 atmospheres, the mol ratio of carbon monoxide to hydrogen being initially from 2:1 to 12.5:1, whereby a reaction occurs resulting in the formation of a mixture of polymethylenes having melting points of 126 to 129 C. as the sole reaction products, said polymethylenes having inherent viscosities of 0.33 to 0.36, measured at 0.25% concentration in tetrahydronaphthalene at 125 C., and thereafter separating the said polymethylenes from the resulting mixture.

3. The process of claim 2 in which the weight of phosphoric acid is of the total Weight of water plus phosphoric acid.

WILLIAM F. GRESHAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,352,328 Kleine June 27, 1944 

1. A PROCESS FOR PREPARING POLYMETHYLENES WHICH COMPRISES INTRODUCING INTO A REACTION VESSEL A MIXTURE OF CARBON MONOXIDE, HYDROGEN, WATER AND AN ACIDIC REAGENT CAPABLE OF MAINTAINING THE PH OF THE MIXTURE BELOW 1, THE MOL RATIO OF CARBON MONOXIDE TO HYDROGEN BEING OF FROM 2:1 TO 12,5:1, HEATING THE SAID MIXTURE IN THE PRESENCE OF A RUTHENIUM-CONTAINING SUBSTANCE AT A TEMPERATURE WITHIN THE RANGE OF TO 225* C. UNDER A PRESSURE WITHIN THE RANGE OF 200 TO 800 ATMOSPHERES, WHEREBY A REACTION OCCURS RESULTING N THE FORMATION OF SOLID POLYMETHYLENES, AND THEREAFTER SEPARATING THE SAID POLYMETHYLENES FROM THE RESULTING MIXTURE. 